Question

Under which of the following condition a Gram positive bacteria turns Gram negative
A) Defective staining technique
B) Changed pH of medium
C) Aged bacterial culture
D) All the above

Answer 1

The answer is A Defective staining technique

Answer 2

The condition when a Gram-positive bacteria turns Gram-negative is     C) Aged bacterial culture.

• Gram-positive and gram-negative bacteria are defined based on the thickness of the peptidoglycan layer of the cell wall
• When a gram-positive bacteria become old then the peptidoglycan layer will also become thin then the gram-positive bacteria turns into either a gram-negative bacteria or gram variable bacteria
• Gram-negative bacteria have an outer lipid membrane while gram-positive bacteria do not have it that is why gram-negative bacteria are harder to kill.